Color photography



July 30 1935- M. zELLl-:R 2,009,424

coLoR PHOTOGRAPHY Filed Aug. 5, 1932 3 Sheets-Sheet 1 mmmm n IlmlwwW-muumuwww 7/////////////////////////////////////7 Narlfl'n Zelle l"mvEN-roR- July 30, 1935- M. zELLl-:R I 2,009,424

coL'oR PHOTOGRAPHY Filed Aug. 5, 1952 3 Sheets-Sheet 2 Groen E/g/ Gre@V6 ff i.'

)mg I A Marn Zeller INVNTOR July 30, 1935. M. ZELLER 2,009,424

coLoR PHOTOGRAPHY Filed Aug. 5, 1932 3 Sheets-Sheet 3 e mi,

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Patented July 30,v 1935 PATENT olelflcr:I l

2,009,424 coLoR PHQ'TOGRAPHY i Martin Zeller, Munich,

Bavaria, Germany, as

signr,by mestre-assignments, to Robert Rchling, Munich, Bavaria, Germanyv ,Application Augustl5, 1932, Serial No. 627,586

In Germany August 14, 1931 18 Claims.

The invention relates to photographic material for use in colorphotography, and to the method of producing photographic pictures,transparent or opaque, in'colors.

According to the invention the light sensitive coating of a plate ornlm, with a color grid or screen applied thereto, is so sensitized thatthe parts covered by the several elements of the screenare,respectively, sensitive to the colors ci those elements only. Greatlyrincreased sharpness ofcoloring is secured by this means.. For sim-' maybe eiected as follows.

First the screen elements of one color` are applied, leaving spaces forthe other elements of the screen. The'coating within these spaces isthen sensitized for'a second color, and the screen ele'- ments of thatcolor are then applied. Generally therewill still be spaces for a thirdcolor, and

' these are then sensitized for that color, the corre-- sponding screenelements beingA subsequently applied. Of course there may be more thanthree colors,',the procedure .being the-same -for each. The screenelements last applied may becolored after applying them tothe plate, bylmeans of a `colorl bath, provided that the elements previously appliedrepel that color, as for .instance by reason of being colored with oilc-jloi". 4All the screen elementsmay be colored with oil or fat colorsif desired, or 'any other convenient color which is resistant to thedeveloping and fixing baths.

If oil colors areused, a treatment for removing the oil or fat 'must beapplied before using the usual `photographic baths, as otherwise thecolors will repel the baths. If the screen .elements last applied areproduced by means cf a bath of a color Vwhich is repelled by thepreviously, applied elements the sensitized coating must receive acoating of gelatine, gum arabic or other suitable col- ]oid, to preventthe bath frompenetrating tothe ,sensitized coating. If'afsoluble coloris usedy for the last applied elements of the screen tlle'photol graphicbaths 'may remove this colo'r, and re`col oring when the plate'is drywill be required, but

insoluble caustic and alcohol colors are available, which render suchre-coloring unnecessary.

The invention will now .be described in detail with reference to theaccompanying' drawings, in which f I' Fig. l diagrammaticallyillustrates one mode of lprocedure for 'taking a colored photographaccording to the invention.I

Fig. 2 is a sectionalview of part of a photographic plate in course ofpreparation.

Figs. 3 to 6 illustrate another 4mode of procedure for preparing aplate.

Fig. 7 illustrates diagrammatically a continuous method-of manufacture,and 'Y Fig. 8 shows portions of two printing rolls used in thatcontinuous method.

Referring first to Fig. 1, 'I' represents a source of light, 2 a groundglass plate for ,diffusing light, 3 a compensatinglight filter, and 4.ascreen negative. made' in the usual way. Behind the screen negativethere is an opaque plate composed of a color screen 5, alight sensitivecoating and a back- IO, with a layer II of white varnish between thecoating 6 and the back. The'coating 9 of the negative l! is between'atransparent plate 8 and a screen I composed of red elements 11, greenelements 'I11 and blue elements 1111.- The elements I4, I3 and I2 of thescreen 5-are of the same colors respectively, but need not be inregister with the corresponding elements of the screen 'I.

Assuming for simplicity that the negative has been produced by-exposureto an object which is uniformly red, only those parts of the coating 9whichare covered by the red elements 'I1 of the 'screen have beenexposed an'd been darkened by the developer. On passing light from the'source I through the diffusing plate 2' and lter 3 the light' raysimpinge at la' great variety of angles upon the negatived, and 'thelight passing through vthe green and blue elements of the screenvnegative fall upon anarea of the color screen 5 which is larger than theaggregate area of the elements 111 and 1111 through which the light .haspassed. The rays strike the elements I2, I 3-and I4 of the color screen,but as they arel colored green and blue they can only pass through theelements I3 and I 2, leaving those parts of the ,coating 6 -which arecovered by the elements I4 unexposed, so'that after developing'thepositive only thev elements I4 show color, the green and blue elementsI3 and I2 appearing dark, by reason 4of their dark background. Referringto Fig. 2,

the manner of producing a photographic plate according to the inventionwill now be described.

A coating 6 which is sensitive to blue light only Vis applied to thevarnish coat II on the back I0,

and is covered with a transparent coating I (e. g. gelatine), which is,permeable to liquid. Then the blue lines or elements I2 of the screenare applied, e. g. by printing, the coloring matter used being one whichrepels dissolved sensitizers.

Those parts of the coating 6 which are not covered by the elements I2are then sensitized for green, or alternatively for yellow oryellow-green. `The blue elements I2 repel this sensitizer, so that onlythe parts between them are affected. The green elements I3 are thenapplied, assuming that the coating has been sensitized for green, andthe coloring matter used in this case is also .one which repelssensitizers. The coating 6 exposed by the gaps |41 is then sensitizedforred, and the coating I5 in the said gaps is then dyed red, as forexample by means of a bath in a solution such as is usedfor red colorfilters, this color being repelled by the blue and green elements o'fthe screen.

By the process described that part of the coating 5 which lies behindeach separate element of the screen, is rendered sensitive to light ofthe color of the said element. The parts covered by the red screenelements are also sensitive to green or yellow-green light, having beensenlsitized for that color, as well as for red.

to blur the picture. "If the coloring matter used.

for the screen, except the elements last applied, repels aqueoussolutions, and the last set of elements has been produced by dyeing thecoating I5 in the gaps vN1 (Fig. 2), the developing bath acts on thecoating 6 by way of these gaps, from which it penetrates under theelements I2, I3. 'Ihe same applies to theflxing bath.

If all the screen eIements'aIe colored with oil or fatty color, in whichcase the coating I5 is not required, theI Yplate must be washed withbenzine or its equivalent in order to enable the developer to acti Incase the objectphotographed is such that whereas a green screen elementis used for the exposure a yellow screen element is required for viewingthe picture thefollowing procedure may be adopted. l

The screen elements are produced with a yellow color, say printers ink,having mixed herewith a blue anilin dye which is subsequently washed outby the photographic baths, leaving purely yellow screen elements. Inmost cases, however, it is sufiicient to use purely yellow elementsAfrom the start. For opaque pictures care shouldv be taken to use for theplate materials such that the screen elements show up with adequatebrightness. f

Bothfor opaque pictures and transparencies the time of exposure requiredis quite short.

Referring to the modification shown in Figs. 3 to,6, the parts I0, 6 andI5 inthese figures are respectively the back, the sensitized coating anda permeable coating, as described with reference to Fig. 2. At I6 thereare resists of fatty color, produced. for example by printing. Theresists have between them gaps I1, of the width of the screen elements.-The coating 6 is first sensitized for a particular color, say green oryellow,

by a sensitizer which acts only inthe gaps I 'I as it is repelled by theresists. After this'the coating I5 is colored green or yellow in thegaps, e. g. by mans of a bath. After drying the plate the resists areremoved (Fig. 4), leaving the plate with yellow or green screen elementsI8 thereon, and with the coating 6 sensitized for yellow or greenunderthese elements.

Then a fresh set of resists I6 is applied, as

shown in Fig. 5, covering the screen elements I8 and an area. of thesame width on one side of each of these elements I8, leaving gaps I9bethis stage to sensitize for blue, the, coa-ting 6 being alreadysensitive to that color.

Of course the plate can be prepared for more than three colors in thisway, and the colors can be applied in any desired order. This method hasthe advantage that the sensitizing of the `coating 6, for the severalcolors, is strictly local, the parts under the red screen elementsbeing,

like the others, sensitive only to light of the color passing throughthe elements which cover them.

In the apparatus shown in Fig. 7 a strip of film 22 is drawn off a reel23 and passes round a roller 24 to a drum 25, whence it travels round aroller 26 to the drying apparatus. Close to the drum surface there aretwo printing rolls 21, 28, for printing on the film screen elements oftwo different colors. Screen elements of a third color are -produced onthe film subsequently, in the gaps between those which have beenprinted. Fig. 8 shows portions of the two printing rolls 21, 28 placedside by side to show the relative positions of the rings 29, 30, whichprint the rulings or lines constituting the screen elements. The gapsbetween the rings are equal to twice the width of the screen elements,so that when one roll has printed a line in a gap between lines printedby the other roll there is still room for an element of another color inthe gap. The printing rolls are inkeddby means of trams of inking rolls3|. The drum rotates clockwise, as Viewed in the drawings. Sensitizingliquid is applied to the film, when it has moved past the roll 2T by aroll, 32 Working in a trough. `Nozzles 33 blow air on to the film, whenit has moved past the roll 32, for the purpose of removing any excess ofliquid which may have been applied. FOI- lowing the roll 28 there` is asensitizing roll 34, and this is followed by blowers 35. There are largenozzles or trunks 36 for blowing air on to the film, for drying it.

'I'he.term sensitizing used in this specification is to be understood asincluding also the process of oversensitizing or hypersensitizing.

The production of colored pictures can also be effected in aphotographic camera, using a plate with a coating selectivelysensitized, respectively partially selectively sensitized, according toJthe colors of the screen elements covering its several parts. After theexposure the plate is developed, and may be subjected to a vreversingprocess whereby the negative is converted into a positive.

It is not necessary to put on the second applying screen elementsimmediately tothe first applied elements. Also it is possible to applythe second elements on any one place within the said light sensitivecoating, said light sensitive V spaces of the rst applied elements. The'now existing free places (after applying the second elements) arecolored with the third (last) color.

In the claims appended the term photographic plate is used in a generalsense to cover also photographic lrns, paper and any other suitablematerial.

,What I claim' as my invention and desire to secure by Letters Patent ofthe United States isz- 1. A photographic plate for color screenpictures, comprising a back 'having a light sensitive coating. thereon,and a color screensubstantially devoid of gaps superimposed on saidcoating, the said coating being locally sensitive within the range ofthe screen elements covering the same in accordance with the colors ofthe several screen elements and insensitive to a substantial portion ofthe visible spectrum below the screen elements oi at least one color.

2. A photographic plate -for color screen pictures, comprising aback'having a light sensitive coating thereon, and a color screensubstantially devoid of gaps and having its elements consisting ofliquid repelling colors superimposed on said coating, the said coatingbeing locally sensitive within the range of the screen elements coveringthe same in accordance with the colors of the several screen elementsand insensitive to a substantial portion of the visible spectrum belowthe screen elements of atleast one color.

3. A photographicplate for color screen pic-- coating being locallysensitive within the rangel of the screen elements covering. the same inaccordance with the colors of the' several screen elements andinsensitive to a substantial portion of the visible spectrum below thescreen elements of at least one color.

hto

4. A photographic plate for color screen pictures, comprising a backhaving a light sensitive coating thereon, a liquid permeable coatingsuperimposed on said light sensitive coating and a color screensubstantially devoid of gaps carried by said-liquid permeable coating,the said light sensitive coating being locally sensitive within therange of the screen elements covering the same in accordance with thecolors of the several screen elements and insensitive to a substantialportion of the visible spectrum below the screen elements of at leastone color.

5. A photographic plate for color screen pictures, comprising a backhaving a light sensitive coating thereon, a liquid permeable coatingsuperimposed on said light sensitive coating, and a color screensubstantially devoid of gaps hav'- ingpart of its elements on thepermeable coating and another part of its elements penetrating -into thepermeable coating through any gaps in the screen, the said-lightsensitive coating being locally sensitive within the range of the screenelements covering the same in accordance with the colors of the severalscreen elements and insensitive to a substantial portion of the visiblespectrum below the screen elements of at least one color.

6. A photographic plate for color screen pictures, comprising a backhaving a light sensitive coating thereon, a liquid permeable coatingsuperimposed on said light sensitive coating, and a color screensubstantially devoid of gaps on coating within the range of `a part onlyof the elements of the screen covering the 'same being locally sensitivein accordance' with the colors of the several screen elements and.insensitive to a substantial` portion of the visible'spectrum be- 'loWthe screen elements of at least one color.

tive within the range of the screen elements covering the'sa'me in'accordance with thecolors of the several screen elements andinsensitive to a substantial portion of the visible spectrum below thescreen elements of at least one color.

8. A photographic plate for color screen pictures, comprising a backhaving a light sensitive coating thereon, a liquid permeable coatingsuperimposed on said light sensitive coating and a color screenincluding yellow elements and 'substantially devoid of gaps, saidscreenv superimposed on said light sensitive layer, said light sensitivecoating Wit-hin the range of the superimposed yellow elements'of thescreen being sensitiv for green light rays within -the range of otherelements of the screen in accordance with the colors oi such otherelements and insensitive to a substantial portion of the visiblespectrum below the scr-een elements of at least one'color.

9. A .photographic plate for color 'screen pictures, comprising a backhaving a light sensitive coating thereon, a liquid permeable coatingsuerimposedon said light sensitive coating 4and a color screen includinggreen elements and substantially devoid of gaps over said lightsensitive coating, said light sensitive coating within the range of thesuperimposed gr-een elements of the screen being sensitive for yellowlight rays within the range of the other elements of the screen inaccordance With the colors of such other elements and insensitive'to asubstantial portion o`f the visible spectrum below the screen elementsof at least one color.

10. A photographic plate for color screen pictures, comprising a backhaving a light sensitive coating thereon, a liquid-permeable coatingsuperimposed on said 'light sensitive coating, and a colorv screensubstantially devoid of gaps `and consisting of a plurality of elementsail of which except one classthereof being color repellent,

said color screen arranged over said light sensitive coating, said lightsensitive 'coating being locally sensitive' within the range' of thescreen elements covering the same in accordance with the colors of theseveral screen elements and insensitive to a substantial portion .of thevisible spectrum below the screen elements of at least one color. c

l1. A photographic plate for color screen pictures, comprising a backhaving a light .sensitive coating thereon, a liquid permeable coatingsuperimposed'on .said light sensitive coating, a light reflecting layerbetween the back and the light sensitive coating, and a color screensubstantially devoid of gaps over the light sensitive coating, saidlight sensitive coating being locally sensitive within the range of thescreen elements covering the same in accordance with spectrum below thescreen elements of at least one color.

12. The process of producing a photographic plate for color photography,comprising applying to a back a coating sensitive to but a single color,applying over said coating a liquid permeable coating, applying to saidpermeable coating the color screen elements of said single color,sensitizing the rst mentioned coating for a second4 color through thepermeable coating in the range of the color screen elements to .beapplied for such second color and applying said second color, continuingthus until all colors but one have been applied, and finally treatingthe plate with a .coloring iluid which is repelled by the previouslyapplied color elements thereby coloring the permeable coating at theplaces left free by the previously applied color elements.

13. The process of producing a photographic plate for color photographycomprising, applying to a back a coating sensitive only to a singlecolor, applying thereupon elements of this color, then 'sensitizing foranother color, applying thev elements of Vthis second color, sensitizingfor the third color and applying the elements of this third color, theportions of the light-sensitive layers covered by the color screen beingnot further sensitized by the subsequent treatment, the sensitizing ofthe light sensitive coating being unnecessary for that color to whichsaid coating is already sensitive.

14. The process of producing a photographic plate for color photographycomprising, applying to a. back a coating sensitive only to one color,printing upon this sensitive coating the eiements of this color withfatty colors, then sensitizing for another color, printing the elementsof this second color with fatty colors, the portions of thelightsensitive layers covered by the color screen being not furthersensitized by the subsequent treatment, sensitizing the rest for a thirdcolor and printing the elements of this third color with fatty colors,the sensitizing of the light sensitive coating being unnecessary forthat color to which said coating is already sensitive.

15,. The process of producing a photographic plate for color photographycomprising, applying to a back a coating sensitive only to a singlecolor, then applying a supplementary screen with the opening of onethird, sensitizing for another color in the gaps spared by the resists,coloring these gaps with the second color, removing the supplementaryscreen and applying ,a second supplementary screen oi the samedimensions as the first mentioned screen but displaced with respect tothe first by the breadth of one element, sensitizing the light sensitivecoating through the gaps of the second screen for the third. color andcoloring with the color corresponding to this sensitizing,l removing thesecond supplementary screen and displacing it so that it covers thecolored elements, coloring the last third of the coating with color towhich the light sensitive coating is already sensitive, the sensitizingof the light sensitive coating being unnecessaryfor that color to whichthe said coating is already sensitive.

16. The process of producing a photographic plate for color photographycomprising, applying to a back a coating sensitive only to a, singlecolor, applying tothe coating a liquid permeable coating, printing uponthe liquid permeable coating an element of the color to which thecoating is already sensitivesensitizing for a second color, printing theelements of the second color, sensitizing the rest for a third color andprinting the elements' of the third color, the portions of thelight-sensitive layers covered by the color screen being not furthersensitized by the subsequent treatment, the sensitizing of the coatingbeing unnecessary for that color to which the said coating is alreadysensitive.

17. The process of producing a photographic plate for color photographycomprising applying upon a back a coating sensitive only to a singlecolor, applying upon this coating a liquid permeable coating, applyingupon the last mentioned coating a supplementary screen with the openingof one third, sensitizing in the gaps spared by the resists for a secondcolor, coloring in said gaps with the second color, removing thesupplementar-y screen and applying another supplementary screen of thesame dimensions as the ilrst mentioned screen but displaced with respectto the iirst by the width of one element, sensitizing the lightsensitive coating through the gaps of the second screen for the thirdcolor and coloring with the color corresponding to this sensitizing,removing the second supplementary screen and displacing it so that itcovers the colored elements, and coloring the last third of the coatingin that color to which the light sensitive coating is already sensitive,the portions of the light-sensitive layers covered by -the color screenbeing not further sensitized by the subsequent treatment.

18. The process of producing a photographic plate for color photographycomprising, applying to a back a coating sensitiveonly to a singlecolor, applying upon this coating a liquid permeable coating, printingthe screen elements of that color to which the coating is alreadysensitive upon the liquid permeable coating, sensitizing for a secondcolor and printing the elements of the second color, sensitizing for thethird color and coloring the liquid permeable coating in the remaininggaps of the third color which corresponds to the last mentionedsensitizing, the portions of the light-sensitive layerscovered by thecolor screen being not furthensensitlzed by the subsequent treatment.

' MARTIN' ZELLER.

